Ring Around the Neck

[Avenger442]

I've had something happen that I haven't seen before and need a little help discovering what it is.

I have been loading up all of my .308 cases. Some are once fired some have been fired 10+ times. On some of the cases the seating die is leaving a ring, kind of like a polished area, about half way down the neck. Feels like it is shaving the case?



Cases on the left have the ring I'm talking about. Cases on the right were loaded at the same time and don't have the ring.
I thought at first it might be a donut on the inside of the neck. But I scratched around with the end of a paper clip and couldn't find one.
Then I thought maybe a bad batch of brass. Most of the areas were on once fired brass. But then I got a couple on brass fired several times.

I'm at a loss. Any suggestions of what to check?

[Winger Ed.]

Maybe the ones with a ring are the older ones and after several firings, the brass has flowed up and is thicker there,
and the neck is rubbing on the inside of the die.

I'd try seating with a known old one and a known once fired case.
Or, measure the neck wall thickness and diameter on a few.

If the wall thickness is thicker on some necks- the expander ball will push the outside diameter out more
than with a thinner walled neck.

[Outpost75]

MEASURE outside diameter of cartridge with bullet seated.

Bullet is OVERSIZE with respect to neck wall thickness of cartridge case.

If cartridge fits snug in seating die so that bullet base impinges against neck wall of cartridge case and is causing a bulge, it probably also lacks safe release clearance for your rifle and may be dangerous to shoot!

[1hole]

Your seater is clearly too small for the combined diameter of your bullet+neck wall thickness so the die's bullet alignment guide is being forced to work as a "sizer" for your necks.

I suspect if you mike your "normal" necks and compare the scraped necks to the unscraped you will find the scraped necks are bigger than the others. It's not common (most seaters are much too sloppy for that to happen) but thick necks and oversized bullets seated in a tight die will do that. Your bullets appear to be cast; if so, what diameter are you casting/sizing them to?

For safety, you can get a very close approximation of your chamber's neck diameter by carefully miking a fired case neck and adding 1 thou to account for normal spring back. If you have even a couple thou clearance between your chamber and the maximum diameter of your loaded rounds you wouldn't be pinching the bullets in place.

[too many things]

dies need good clean job

[Avenger442]

Winger Ed
Most of the rings are happening on once fired brass

Outpost 75
Will do some measuring

1hole
Yes cast and coated with gas check. Bullets were sized .309.
Will measure neck on fired case add .001 and see if polished area is too big for chamber.

too many things
Die is Hornady cleaned about fifty rounds ago.

Since it is not happening with every case it's probably not the die but the case. First time it happened I was sure it was because of what Winger said, brass flow. So I checked for "donut" in the neck and didn't find one. I mark my cases once for each firing and when I looked most of the cases were once fired. Some of my cases have been fired more than ten times. None of those has the polished area.

Thanks for the replys. Not going to deal with it soon have computer problems and dealing with Microsoft is taking some time. May have to go to Geek Squad.

[elmacgyver0]

I first thought this might be about laundry.

[Avenger442]

[Ozark mike]

Ya I was thinking about when dad got mad and Decided to reduce the blood flow to the top of my head. But in all seriousness id measure the case before and after seating cause i get that with oversize bullets in cases sized to small

[murf205]

I had some brass just like that Avenger and mine was from brass that was blanks. The ring is where the neck was crimped to form the point on the blank cases. I shot it with no apparent problems till the primer pockets got too big. Like Outpost 75 said, measure the necks with a boolit seated in the case and compare it to one that has no ring and has PROVEN to not spike pressures.

[Alferd Packer]

Maybe back out the whole die a quarter inch and run the seater rod.back down a quarter inch and see what happens.
I dont know if this is doable.

[Avenger442]

I got another thought on this. Maybe it is the bullet. Even though they have been sized 309 are they? So I measured the gas checks on several. They were from .3095 to .311. Aah haa I found it. So I loaded several of the .3095 to .311 and it didn't make a difference. All caused the ring on some rounds. Then I measured where the gas check was when loaded and it is below the ring. So I'm back to believing it is the case. But why? Some are once fired a few are several firings.

And another interesting thing has happened. Two of the last ones loaded do not have the ring all the way around the neck. I may turn the outside of the necks after firing. All measurements indicate that they are safe to fire. Also cycled them through two bolt rifles. No indication of sticking going in or coming out.

[Winger Ed.]

They chamber up OK. That's a good sign.

Does a bullet- particularly a jacketed one, just drop into the fired case like you'd expect?
If it won't drop back in, that may be getting back to the necks being too thick to expand properly on firing.

[Avenger442]

They chamber up OK. That's a good sign.

Does a bullet- particularly a jacketed one, just drop into the fired case like you'd expect?
If it won't drop back in, that may be getting back to the necks being too thick to expand properly on firing.

Can't check that on these. All hVe been resized and primer in place.